title: Effect of odanacatib on bone turnover markers, bone density and geometry of the spine and hip of ovariectomized monkeys: a head-to-head comparison with alendronate.
abstract: Odanacatib (ODN) is a selective and reversible Cathepsin K (CatK) inhibitor currently being developed as a once weekly treatment for osteoporosis. Here, effects of ODN compared to alendronate (ALN) on bone turnover, DXA-based areal bone mineral density (aBMD), QCT-based volumetric BMD (vBMD) and geometric parameters were studied in ovariectomized (OVX) rhesus monkeys. Treatment was initiated 10 days after ovariectomy and continued for 20 months. The study consisted of four groups: L-ODN (2 mg/kg, daily p.o.), H-ODN (8/4 mg/kg daily p.o.), ALN (15 μg/kg, twice weekly, s.c.), and VEH (vehicle, daily, p.o.). L-ODN and ALN doses were selected to approximate the clinical exposures of the ODN 50-mg and ALN 70-mg once-weekly, respectively. L-ODN and ALN effectively reduced bone resorption markers uNTx and sCTx compared to VEH. There was no additional efficacy with these markers achieved with H-ODN. Conversely, ODN displayed inversely dose-dependent reduction of bone formation markers, sP1NP and sBSAP, and L-ODN reduced formation to a lesser degree than ALN. At month 18 post-OVX, L-ODN showed robust increases in lumbar spine aBMD (11.4%, p<0.001), spine trabecular vBMD (13.7%, p<0.001), femoral neck (FN) integral (int) vBMD (9.0%, p<0.001) and sub-trochanteric proximal femur (SubTrPF) int vBMD, (6.4%, p<0.001) compared to baseline. L-ODN significantly increased FN cortical thickness (Ct.Th) and cortical bone mineral content (Ct.BMC) by 22.5% (p<0.001) and 21.8% (p<0.001), respectively, and SubTrPF Ct.Th and Ct.BMC by 10.9% (p<0.001) and 11.3% (p<0.001) respectively. Compared to ALN, L-ODN significantly increased FN Ct. BMC by 8.7% (p<0.05), and SubTrPF Ct.Th by 7.6% (p<0.05) and Ct.BMC by 6.2% (p<0.05). H-ODN showed no additional efficacy compared to L-ODN in OVX-monkeys in prevention mode. Taken together, the results from this study have demonstrated that administration of ODN at levels which approximate clinical exposure in OVX-monkeys had comparable efficacy to ALN in DXA-based aBMD and QCT-based vBMD. However, FN cortical mineral content clearly demonstrated superior efficacy of ODN versus ALN in this model of estrogen-deficient non-human primates.
authors.affiliation: Merck Sharp and Dohme Corp., Whitehouse Station, NJ, USA. donald_williams686@gmail.com
authors.forename: Donald S
authors.initials: DS
authors.lastname: Williams
authors.forename: Paul J
authors.initials: PJ
authors.lastname: McCracken
authors.forename: Mona
authors.initials: M
authors.lastname: Purcell
authors.forename: Maureen
authors.initials: M
authors.lastname: Pickarski
authors.forename: Parker D
authors.initials: PD
authors.lastname: Mathers
authors.forename: Alan T
authors.initials: AT
authors.lastname: Savitz
authors.forename: John
authors.initials: J
authors.lastname: Szumiloski
authors.forename: Richa Y
authors.initials: RY
authors.lastname: Jayakar
authors.forename: Sangeetha
authors.initials: S
authors.lastname: Somayajula
authors.forename: Stephen
authors.initials: S
authors.lastname: Krause
authors.forename: Keenan
authors.initials: K
authors.lastname: Brown
authors.forename: Christopher T
authors.initials: CT
authors.lastname: Winkelmann
authors.forename: Boyd B
authors.initials: BB
authors.lastname: Scott
authors.forename: Lynn
authors.initials: L
authors.lastname: Cook
authors.forename: Sherri L
authors.initials: SL
authors.lastname: Motzel
authors.forename: Richard
authors.initials: R
authors.lastname: Hargreaves
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Evelhoch
authors.forename: Antonio
authors.initials: A
authors.lastname: Cabal
authors.forename: Bernard J
authors.initials: BJ
authors.lastname: Dardzinski
authors.forename: Thomas N
authors.initials: TN
authors.lastname: Hangartner
authors.forename: Le T
authors.initials: LT
authors.lastname: Duong
mesh_terms: D019386:Alendronate / Q000493:pharmacokinetics / Q000627:therapeutic use*; D000818:Animals; D001713:Biphenyl Compounds / Q000493:pharmacokinetics / Q000627:therapeutic use*; D015519:Bone Density / Q000187:drug effects*; D050071:Bone Density Conservation Agents / Q000493:pharmacokinetics / Q000627:therapeutic use; D016723:Bone Remodeling / Q000187:drug effects; D005260:Female; D000882:Haplorhini; D006621:Hip Joint / Q000000981:diagnostic imaging / Q000187:drug effects; D010052:Ovariectomy; D011859:Radiography; D013131:Spine / Q000000981:diagnostic imaging / Q000187:drug effects
chemical_list: D001713:Biphenyl Compounds; D050071:Bone Density Conservation Agents; C527128:odanacatib; D019386:Alendronate
keywords: Bone turnover marker; Cathepsin K inhibitor; Odanacatib